The severity of the clinical manifestations of sickle cell anemia is related in part to the concentration of hemoglobin S within the red cell. Sickle cell anemia patients however, who continue to synthesize high concentrations of fetal hemoglobin may be relatively asymptomatic. Our project is designated to investigate by in vitro methods whether control of specific gene expression is possible. In particular we are interested in establishing the most feasible means to increase the synthesis of fetal hemoglobin and to modulate the synthesis of hemoglobin S within the cells of patients with sickle cell anemia. We hope that information gained in this manner will prove valuable to clinicians in the treatment of sickle cell anemia.